针对CD上24套 中缺少题目和部分语言错误作出了修正 补充了部分题目和拼写错误 欢迎大家讨论

24-1 Tom Bradley was mayor of Los Angeles from 1973 to 1993, an era when the city had transformed from a collection of suburban neighborhoods to the second-largest city in the United States.

A. an era when the city had transformed

B. an era during which the city was transformed

C. an era that transformed it

D. during which era the city transformed

E. during which the city was transformed

24-2 According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.

A. than

B. than born

C. than they were

D. than there had been

E. than had been born

24-Passage one

More selective than most chemical pesticides in that they ordinarily destroy only unwanted species, biocontrol agents (such as insects, fungi, and viruses) eat, infect, or parasitize targeted plant or animal pests. However, biocontrol agents can negatively affect nontarget species by, for example, competing with them for resources: a biocontrol agent might reduce the benefits conferred by a desirable animal species by consuming a plant on which the animal prefers to lay its eggs.(Line 14) Another example of indirect negative consequences occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a blue butterfly that had depended on the nests to shelter its offspring. The paucity of known extinctions or disruptions resulting from indirect interactions may reflect not the infrequency of such mishaps but rather the failure to look for or to detect them: most organisms likely to be adversely affected by indirect interactions are of little or no known commercial value and the events linking a biocontrol agent with an adverse effect are often unclear. Moreover, determining the potential (35) risks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced, because, unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways, so that it can feed on or otherwise harm new hosts.

24-3 The passage is primarily concerned with

A. explaining why until recently scientists failed to recognize the risks presented by biocontrol agents.

B. emphasizing that biocontrol agents and chemical pesticides have more similarities than differences.

C. suggesting that only certain biocontrol agents should be used to control plant or animal pasts.

D. arguing that biocontrol agents involve risks, some of which may not be readily discerned.

E. suggesting that mishaps involving biocontrol agents are relatively commonplace.

24-4 The passage suggests that the author would be most likely to agree with which of the

following statements about the use of biocontrol agents?

A. biocontrol agent should be used only in cases where chemical pesticides have proven ineffective or overly dangerous.

B. extinctions and disruptions resulting from the use of biocontrol agents are likely to have increasingly severe commercial consequences.

C. the use of biocontrol agents does not require regulation as stringent as that required by the use of chemical pesticides.

D. the use of biocontrol agents may even finally supersede the use of chemical pesticides in controlling unwanted species.

E. the risks of using native biocontrol agents may be easier to predict than the risks of using nonnative biocontrol agents.

24-5 Which of the following is mentioned in the passage as an indirect effect of using a biocontrol agent?

A. reduction of the commercial value of a desirable animal species

B. an unintended proliferation of a nontarget animal species

C. an unforeseen mutation in a target species

D. diminution of the positive effects conferred by a nontarget animal species

E. competition for resources with a largest species

24-6 The example presented by the author in lines 14-23 most clearly serves to illustrate

A. a situation in which a species is less vulnerable to biocontrol agents than it would have been to chemical pesticides.

B. a way in which the introduction of a biocontrol agent can affect a nontarget species.

C. a nonnative agent’s adapting in an unpredictable way that results in damage to a new host.

D. the contention that biocontrol agents can harm nontarget species by competing with them for resources.

E. the way in which indirect consequences from the use of biocontrol agents are most likely to occurs.

24-7 Which of the following most logically completes the argument below?

The expansion of large-scale farming in Africa and Asia has destroyed much of the natural

vegetation on which elephants have historically depended, forcing them to turn to cultivated

land to satisfy their enormous appetites. As a result, farmers have lost millions of dollars worth

of crops annually. Yet even if elephant sanctuaries were created on a widespread basis to

guarantee elephants sufficient natural vegetation, the raiding would likely persist, since

A. when elephants forage for food, they typically travel in herds.

B. foraging elephants have been known to cause substantial damage even to plants that they do not eat.

C. some of the land where crops have suffered extensive damage from elephants has been allowed to return to its natural state.

D. elephants tend to prefer cultivated crops to wild vegetation as a food source

E. elephant sanctuaries are usually created in areas that are rich in the natural vegetation on which elephants have historically depended.

24-8 The results of the company’s cost-cutting measures are evident in its profits, which

increased five percent during the first three months of this year after it fell over the last two

years.

A. which increased five percent during the first three months of this year after it fell

B. which had increased five percent during the first three months of this year after it had fallen

C. which have increased five percent during the first three months of this year after falling

D. with a five percent increase during the first three months of this year after falling

E. with a five percent increase during the first three months of this year after having fallen

24-9 Part of the proposed increase in state education spending is due to higher enrollment,

since the number of students in public schools have grown steadily since the mid-1980’s and, at

nearly 47 million, are at a record high.

A. enrollment, since the number of students in public schools have grown steadily since the mid-1980’s and, at nearly 47 million, are at

B. enrollment, with a number of students in public schools growing steadily since the mid-1980’s and, at nearly 47 million, reaching

C. enrollment: since students in public schools have grown steadily in number since the mid-1980’s and, at nearly 47 million, have reached

D. enrollment: the number of student in public schools has grown steadily since the mid-1980’s and, at nearly 47 million, has reached

E. enrollment: students in public schools have grown steadily in number since the mid-1980’s and, at nearly 47 million, are at

24-passage two

Is it possible to decrease inflation without causing a recession and its concomitant increase in unemployment? The orthodox answer is “no”. Whether they support the “inertia” theory of inflation(that today’s inflation rate is caused by yesterday’s inflation, the state of the economic cycle, and external influences such as import prices) or the “rational expectations” theory (that inflation is caused by workers’ and employers’ expectations, coupled with a lack of credible monetary and fiscal policies), most economists agree that tight monetary and fiscal policies, which cause recessions, are necessary to decelerate inflation. They point out that in the 1980’s, many European countries and the United States conquered high (by these countries’ standards) inflation, but only by applying tight monetary and fiscal policies that sharply increased unemployment. Nevertheless, some governments’ policymakers insist that direct controls on wages and prices, without tight monetary and fiscal policies, can succeed in decreasing inflation. Unfortunately, because this approach fails to deal with the underlying causes of inflation, wage and price controls eventually collapse, the hitherto-repressed inflation resurfaces, and in the meantime, though the policy-makers succeed in avoiding a recession, a frozen structure of relative prices imposes distortions that do damage to the economy’s prospects for long-term growth.

24-10 The passage suggests that the high inflation in the United States and many European countries in the 1980’s differed from inflation elsewhere in which of the following ways?

A. It fit the rational expectations theory of inflation but not the inertia theory of inflation.

B. It was possible to control without causing a recession.

C. It was easier to control in those countries by applying tight monetary and fiscal policies than it would have been elsewhere.

D. It was not caused by workers’ and employers’ expectations.

E. It would not necessarily be considered high elsewhere.

24-11 Which of the following, if true, would most strengthen the author’s conclusion about the use of wage and price controls?

A. Counties that repeatedly use wage and price controls tend to have lower long-term economic growth rates than do other countries.

B. Countries that have extremely high inflation frequently place very stringent controls on wages and prices in an attempt to decrease the inflation.

C. Some countries have found that the use of wage and price controls succeeds in decreasing inflation but also causes a recession.

D. Policymakers who advocate the use of wage and price controls believe that these controls will deal with the underlying causes of inflation.

E. Policymakers who advocate the use of wage and price controls are usually more concerned about long-term economic goals than about short-term economic goals

24-12 The primary purpose of the passage is to

A. apply two conventional theories.

B. examine a generally accepted position.

C. support a controversial policy.

D. explain the underlying causes of a phenomenon.

E. propose an innovative solution.

24-13 Vivien Thomas, who had no formal medical training, in struggling against overwhelming odds, he became a cardiac surgeon and eventually to receive an honorary doctorate from Johns Hopkins University.

A. who had no formal medical training, in struggling against overwhelming odds, he became

B. having had no formal medical training, in struggling against overwhelming odds to become

C. who, having no formal medical training, he struggled against overwhelming odds in becoming

D. who, having had no formal medical training and struggled against overwhelming odds, became

E. who had no formal medical training, struggled against overwhelming odds to become

24-14: In 1983 Argonia’s currency, the argon, underwent a reduction in value relative to the world’s strongest currencies. This reduction resulted in a significant increase in Argonia’s exports over 1982 levels. In 1987 a similar reduction in the value of the argon led to another increase in Argonia’s exports. Faced with the need to increase exports yet again, Argonia’s finance minister has proposed another reduction in the value of the argon.

Which of the following, if true, most strongly supports the prediction that the finance minister’s plan will not result in a significant increase in Argonia’s exports next year?

A. The value of the argon rose sharply last year against the world’s strongest currencies.

B. In 1988 the argon lost a small amount of its value, and Argonians exports rose slightly in 1989.

C. The value of Argonia’s exports was lower last year than it was the year before.

D. All of Argonia’s export products are made by factories that were operating at full capacity last year, and new factories would take years to build.

E. Reductions in the value of the argon have almost always led to significant reductions in the amount of goods and services that Argonians purchase from abroad.

24-15 Healthy lungs produce a natural antibiotic that protects them from infection by routinely killing harmful bacteria on airway surfaces. People with cystic fibrosis, however, are unable to fight off such bacteria, even though their lungs produce normal amounts of the antibiotic. Since the fluid on airway surfaces in the lungs of people with cystic fibrosis has an abnormally high salt concentration, scientists hypothesize that in high salt environments the antibiotic becomes ineffective at killing harmful bacteria.

Which of the following, if it were obtained as an experimental result, would most decisively undermine the scientists’ hypothesis?

A. Healthy lungs in which the salt concentration of the airway-surface fluid has been substantially increased are able to reestablish their normal salt concentration within a relatively short period of time.

B. The antibiotic produced by the lungs is effective at killing harmful bacteria even when salt concentrations are below levels typical of health lungs.

C. The salt concentration of the airway-surface fluid in the lungs of people who suffer from cystic fibrosis tends to return to its former high levels after having been reduced to levels typical of healthy lungs.

D. The lungs of people who suffer from cystic fibrosis are unable to fight off harmful bacteria even when the salt concentration is reduced to levels typical of healthy lungs.

E. The salt concentration in the airway-surface fluid of people whose lungs produce lower-than-average amounts of the antibiotic is generally much lower than that typical of healthy lungs.

24-16 Which of the following most logically completes the argument below?

According to promotional material published by the city of Springfield, more tourists stay in hotels in Springfield than stay in the neighboring city of Harristown. A brochure from the largest hotel in Harristown claims that more tourist stay in that hotel than stay in the Royal Arms Hotel in Springfield. If both of these sources are accurate, however, the “Report on Tourism” for the region must be in error in stating that

A. the average length of stay is longer at the largest hotel in Harristown than it is at the Royal Arms Hotel.

B. There is only one hotel in Harristown that is larger than the Royal Arms Hotel.

C. More tourist stay in hotels in Harristown than stay in the Royal Arms Hotel.

D. The Royal Arms hotel is the largest hotel in Springfield.

E. The royal arms hotel is the only hotel in Springfield.

24-17 The yield of natural gas from Norway’s Troll gas field is expected to increase annually until the year 2005 and then to stabilize at six billion cubic feet a day, which will allow such an extraction rate at least for 50 years’ production.

A. 2005 and then to stabilize at six billion cubic feet a day, which will allow such an extraction rate at least for

B. 2005 and then to stabilize at six billion cubic feet a day, an extraction rate that will allow at least

C. 2005 and then stabilizing at six billion cubic feet a day, with such an extraction rate at the least allowing

D. 2005, then stabilizing at six billion cubic feet a day, allowing such an extraction rate for at least

E. 2005, then stabilizing at six billion cubic feet a day, which will allow such an extraction rate for at least

24-18 Most household appliances use electricity only when in use. Many microwave ovens, however, have built-in clocks and so use some electricity even when they are not in use. The clocks each consume about 45 kilowatt-hours per year. Therefore, households whose microwave oven has no built-in clock use 45 kilowatt-hours per year less. On average, than do comparable households whose microwave oven is otherwise similar but has a built-in clock.

Which of the following is an assumption on which the argument depends?

A. Households that do not have a microwave oven use less energy per year, on average, than do households that have a microwave oven.

B. Microwave ovens with a built-in clock do not generally cost more to buy than microwave ovens without a built-in clock.

C. All households that have a microwave oven also have either a gas oven or a conventional electric oven.

D. Households whose microwave oven does not have a built-in clock are no more likely to have a separate electric clock plugged in than households whose microwave oven has one

E. There are more households that have a microwave oven with a built-in clock than there are households that have a microwave oven without a built-in clock.

24-19 In archaeology, there must be a balance between explanation of the value and workings of archaeology, revealing the mysteries of past and present cultures, and to promote respect for archaeological sites.

A. between explanation of the value and workings of archaeology, revealing the mysteries of past and present cultures, and to promote

B. among explaining the value and workings of archaeology, revealing the mysteries of past and present cultures, and promoting

C. between explaining the value and workings of archaeology, revealing the mysteries of past and present cultures, and when promoting

D. among explaining the value and workings of archaeology, the revelation of the mysteries of past and present cultures, and to promote

E. between explaining archaeology’s value and workings, in the revealing the mysteries of past and present cultures, and in promoting

24-20 According to a 1996 survey by the National Association of College an University Business Officers, more than three times as many independent institutions of higher education charge tuition and fees of under $8,000 a year than those that charge over $16,000.

A. than those that charge

B. than are charging

C. than to charge

D. as charge

E. as those charging

24-21 Nobody knows exactly how many languages there are in the world, partly because of the difficulty of distinguishing between a language and the sub-languages or dialects within it, but those who have tried to count typically have found about five thousand.

A. and the sub-languages or dialects within it, but those who have tried to count typically have found

B. and the sub-languages or dialects within them, with those who have tried counting typically finding

C. and the sub-languages or dialects within it, but those who have tried counting it typically find

D. or the sub-languages or dialects within them, but those who tried to count them typically found

E. or the sub-languages or dialects within them, with those who have tried to count typically finding

24-22 Often patients with ankle fractures that are stable, and thus do not require surgery, are given follow-up x-ray because their orthopedists are concerned about possibly having misjudged the stability of the fracture. When a number of follow-up x-rays were reviewed, however, all the fractures that had initially been judged stable were found to have healed correctly. Therefore, it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable.

Which of the following, if true, most strengthens the argument?

A. Doctors who are general practitioners rather than orthopedists are less likely than orthopedists to judge the stability of an ankle fracture correctly.

B. Many ankle injuries for which an initial x-ray is ordered are revealed by the x-ray not to involve any fracture of the ankle.

C. X-rays of patients of many different orthopedists working in several hospitals were reviewed.

D. The healing of ankle fractures that have been surgically repaired is always checked by means of a follow-up x-ray.

E. Orthopedists routinely order follow-up x-rays for fractures of bone other than ankle bones.

24-23 Discussion of greenhouse effects has usually focused on whether the Earth would warm and by how much, but climatologists have indicated all along that the most obvious effects, and those that would have the largest impact on people, would be extremes of temperature, precipitation, and storminess.

A. the most obvious effects, and those that would have the largest impact on people, would be extremes of temperature, precipitation, and storminess.

B. the effects that are the most obvious ones, extremes of temperature, precipitation, and storminess, would be those impacting the most on people.

C. those effects to have the largest impact on people, extremes of temperature, precipitation, and storminess, are what are the most obvious effects.

D. extremes of temperature, precipitation, and storminess, the most obvious effects, that they would have the largest impact on people.

E. extremes of temperature, precipitation, and storminess, which are the most obvious effects, are those to impact the most on people.

24-24 Many winemakers use cork stoppers; but cork stoppers can leak, crumble, or became moldy, so that those winemakers must often discard a significant proportion of their inventory of bottled wine. Bottlemaster plastic stoppers, which cannot leak, crumble, or mold, have long been available to winemakers, at a price slightly higher than that of traditional cork stoppers. Cork prices, however, are expected to rise dramatically in the near future. Clearly, therefore, winemakers who still use cork but wish to keep production costs from rising will be forced to reconsider plastic stoppers. And since the wine-buying public’s association of plastic stoppers with poor-quality wine is weakening, there is an excellent chance that the Bottlemaster plastic stopper will gain an increased share of the market for wine-bottle stoppers.

In the argument given, the two portions in boldface play which of the following roles?

A. The first is a judgment that has been advanced in support of a position that the argument opposes; the second is the main conclusion of the argument.

B. The first is a judgment that has been advanced in support of a position that the argument opposes; the second is conclusion drawn in order to support the main conclusion of the argument.

C. The first is the main conclusion of the argument; the second provides evidence in support of that main conclusion.

D. The first is the main conclusion of the argument; the second is a restatement of that main conclusion.

E. The first is a conclusion drawn in order to support the main conclusion of the argument; the second is that main conclusion.

24-passage three

In a 1918 editorial, W.E.B. Du Bois advised African Americans to stop agitating for equality and to proclaim their solidarity with White Americans for the duration of the First World War. The editorial surprised many Africa Americans who viewed Du Bois as an uncompromising African American leader and a chief opponent of the (10) accommodationist tactics urged by Booker, T. Washington. In fact, however, Du Bois often shifted positions along the continuum between Washington and confrontationists (15) such as William Trotter. In 1895, when Washington called on African Americans to concentrate on improving their communities instead of opposing discrimination and agitating for (20) political rights, Du Bois praised Washington’s speech. In 1903, however, Du Bois aligned himself with Trotter, Washington’s militant opponent, less for ideological reasons (25) than because Trotter had described to him Washington’s efforts to silence those in the African American press who opposed Washington’s positions.(20)reflected not a change in his long-term goals but rather a pragmatic response in the face of social pressure: government officials had threatened African American journalists with censorship if they continued to voice grievances. Furthermore, Du Bois believed that African Americans’ contributions to past war efforts had brought them some legal and political (40) advances. Du Bois’ accommodationism did not last, however. Upon learning of systematic discrimination experienced by African Americans in the military, he called on them to “return fighting” from the war.

24-25: According to the passage, which of the following is true of the strategy that Du Bois’ 1918 editorial urged African Americans to adopt during the First World War?

A. It was a strategy that Du Bois had consistently rejected in the past.

B. It represented a compromise between Du Bois’ own views and those of Trotter.

C. It represented a significant redefinition of the long-term goals Du Bois held prior to the war.

D. It was advocated by Du Bois in response to his recognition of the discrimination faced by African Americans during the war.

E. It was advocated by Du Bois in part because of his historical knowledge of gains African Americans had made during past wars.

24-26: The passage is primarily concerned with

A. identifying historical circumstances that led Du Bois to alter his long-term goals.

B. defining “accommodationism” and showing how Du Bois used this strategy to achieve certain goals.

C. accounting for a particular position adopted by Du Bois during the First World War.

D. contesting the view that Du Bois was significantly influenced by either Washington or Trotter.

E. assessing the effectiveness of a strategy that Du Bois urged African Americans to adopt.

24-27: The passage indicates which of the following about Du Bois’ attitude toward Washington?

A. It underwent a shift during the First World War as Du Bois became more sympathetic with Trotter’s views.

B. It underwent a shift in 1903 for reasons other than Du Bois’ disagreement with Washington’s accommodationist views.

C. It underwent a shift as Du Bois made a long-term commitment to the strategy of accommodation.

D. It remained consistently positive even though Du Bois disagreed with Washington’s efforts to control the African American press.

E. It was shaped primarily by Du Bois’ appreciation of Washington’s pragmatic approach to the advancement of the interests of African Americans.

24-28: Unlike most severance packages, which require workers to stay until the last day scheduled to collect, workers at the automobile company are eligible for its severance package even if they find a new job before they are terminated.

A. the last day scheduled to collect, workers at the automobile company are eligible for its severance package

B. the last day they are scheduled to collect, workers are eligible for it the automobile company’s severance package

C. their last scheduled day to collect, the automobile company offers its severance package to workers.

D. their last scheduled day in order to collect, the automobile company’s severance package is available to workers.

E. the last day that they are scheduled to collect, the automobile company’s severance package is available to workers.

24-29: Plant scientists have been able to genetically engineer vegetable seeds to produce crops that are highly resistant to insect damage. Although these seeds currently cost more than conventional seeds, their cost is likely to decline. Moreover, farmers planting them can use far less pesticide, and most consumers prefer vegetables grown with less pesticide, therefore, for crops for which these seeds can be developed, their use is likely to become the norm.

Which of the following would be most useful to know in evaluating the argument above?

A. Whether plant scientists have developed insect-resistant seeds for every crop that is currently grown commercially?

B. Whether farmers typically use agricultural pesticides in large amounts than is necessary to prevent crop damage?

C. Whether plants grown from the new genetically engineered seeds can be kept completely free of insect damage?

D. Whether seeds genetically engineered to produce insect-resistant crops generate significantly lower per acre crop yields than do currently used seeds?

E. Whether most varieties of crops currently grown commercially have greater natural resistance to insect damage than did similar varieties in the past.

24-passage four

In most earthquakes the Earth’s crust cracks like porcelain. Stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. Some earthquakes, however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. How can there be earthquakes at such depths?

That such deep events do occur has been accepted only since 1927, when the seismologist Kiyoo Wadati convincingly demonstrated their existence. Instead of comparing the arrival times of seismic waves at different locations, as earlier researchers had done, Wadati relied on a time difference between the arrival of primary (P) waves and the slower secondary (S) waves. Because P and S waves travel at different but fairly constant speeds, the interval between their arrivals increases in proportion to the distance from the earthquake focus, or initial rupture point. For most earthquakes, Wadati discovered, the interval was quite short near the epicenter; the point on the surface where shaking is strongest. For a few events, however, the delay was long even at the epicenter. Wadati saw a similar pattern when he analyzed data on the intensity of shaking. Most earthquakes had a small area of intense shaking, which weakened rapidly with increasing distance from the epicenter, but others were characterized by a lower peak intensity, felt over a broader area. Both the P-S intervals and the intensity patterns suggested two kinds of earthquakes: the more (45) common shallow events, in which the focus lay just under the epicenter, and deep events, with focus several hundred kilometers down.

The question remained: how can such quakes occur, given that mantle rock at a depth of more than 50 kilometers is too ductile to store enough stress to fracture? Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.

24-30 The author’s explanation of how deep events occur would be most weakened if which of the following were discovered to be true?

A. Deep events are far less common than shallow events.

B. Deep events occur in places other than where crustal plates meet.

C. Mantle rock is more ductile at a depth of several hundred kilometers than it is at 50 kilometers.

D. The speeds of both P and S waves are slightly greater than previously thought.

E. Below 650 kilometers earthquakes cease to occur.

24-31 Information presented in the passage suggests that, compared with seismic activity at the epicenter of a shallow event, seismic activity at the epicenter of a deep event is characterized by

A. shorter P-S intervals and higher peak intensity

B. shorter P-S intervals and lower peak intensity

C. longer P-S intervals and similar peak intensity

D. longer P-S intervals and higher peak intensity

E. longer P-S intervals and lower peak intensity

24-32 The passage supports which of the following statements about the relationship between the epicenter and the focus of an earthquake?

A. P waves originate at the focus and S waves originate at the epicenter.

B. In deep events the epicenter and the focus are reversed.

C. In shallow events the epicenter and the focus coincide

D. In both deep and shallow events the focus lies beneath the epicenter

E. The epicenter is in the crust, whereas the focus is in the mantle.

24-33 The passage suggests that which of the following must take place in order for any earthquake to occur?

I. Stress must build up

II. Cool rock must descend into the mantle.

III. A fracture must occur.

A. I only

B. II only

C. III only

D. I and III only

E. I, II and III

24-34 Studying the fruit fly, a household nuisance but a time-honored experimental subject, has enabled the secrets of how embryos develop to begin to be unraveled by scientists.

A. Studying the fruit fly, a household nuisance but a time-honored experimental subject, has enabled the secrets of how embryos develop to begin to be unraveled by scientists.

B. By the study of the fruit fly, a household nuisance and also a time-honored experimental subject, it was possible for the secrets of how embryos develop to begin to be unraveled by scientists.

C. By studying a household nuisance but a time-honored experimental subject, the fruit fly enabled scientists to begin to unravel the secrets of how embryos develop.

D. By studying the fruit fly, a household nuisance and also a time-honored experimental subject, the secrets of how embryos develop are beginning to be unraveled by scientists.

E. The study of the fruit fly, a household nuisance but a time-honored experimental subject, has enabled scientists to begin to unravel the secrets of how embryos develop.

24-35: The milk of many mammals contains cannabinoids, substances that are known to stimulate certain receptors in the brain. To investigate the function of cannabinoids, researchers injected newborn mice with a chemical that is known to block cannabinoides from reaching their receptors in the brain. The injected mice showed far less interest in feeding than normal newborn mice do. Therefore, cannabinoids probably function to stimulate the appetite.

Which of the following is an assumption on which the argument depends?

A. Newborn mice do not normally ingest any substance other than their mothers’ milk.

B. Cannabinoids are the only substances in mammals’ milk that stimulate the appetite.

C. The mothers of newborn mice do not normally make any effort to encourage their babies to feed.

D. The milk of mammals would be less nutritious if it did not contain cannabinoids.

E. The chemical that blocks cannabinoids from stimulating their brain receptors does not independently inhibit the appetite.

24-36: The Industrial Revolution, making it possible to mass-produce manufactured goods, was marked by their use of new machines, new energy sources, and new basic materials.

A. making it possible to mass-produce manufactured goods, was marked by their use of

B. making possible the mass production of manufactured goods, marked by the use of

C. which made it possible that manufactured goods were mass-produced, was marked by their using

D. which made possible the mass-production of manufactured goods, was marked by the use of

E. which made the mass production of manufactured goods possible and was marked by using

24-37 Fish currently costs about the same at seafood stores throughout Eastville and its

surrounding suburbs. Seafood stores buy fish from the same wholesalers and at the same prices, and other business expenses have also been about the same. But new tax breaks will

substantially lower the cost of doing business within the city. Therefore, in the future, profit

margins will be higher at seafood stores within the city than at suburban seafood stores.

For the purpose of evaluating the argument, it would be most useful to know whether

A. more fish wholesalers are located within the city than in the surrounding suburbs.

B. any people who currently own seafood stores in the suburbs surrounding Eastville will relocate their businesses nearer to the city

C. the wholesale price of fish is likely to fall in the future

D. Fish has always cost about the same at seafood stores throughout Eastville and its surrounding suburbs.

E. Seafood stores within the city will in the future set prices that are lower than those at suburban seafood stores.

24-38 In January 1994 an oil barge ran aground off the coast of San Juan, Puerto Rico, leaking its cargo of 750000 gallons into the ocean, while causing the pollution of the city’s beaches.

A. leaking its cargo of 750000 gallons into the ocean, while causing the pollution of

B. with its cargo of 750000 gallons leaking into the ocean, and it polluted

C. and its cargo of 750000 gallons leaked into the ocean, polluting

D. while it leaked its cargo of 750000 gallons into the ocean and caused the pollution of

E. so that its cargo of 750000 gallons leaked into the ocean, and they were polluting

24-39 Japan’s abundant rainfall and the typically mild temperature throughout most of the country have produced a lush vegetation cover and, despite the mountainous terrain and generally poor soils, it has made possible the raising of a variety of crops.

A. it has made possible the raising of

B. has made it possible for them to raise

C. have made it possible to raise

D. have made it possible for raising

E. thus making it possible for them to raise

24-40 Scientists typically do their most creative work before the age of forty. It is commonly thought that this happens because aging by itself brings about a loss of creative capacity. However, studies show that a disproportionately large number of the scientists who produce highly creative work beyond the age of forty entered their field at an older age than is usual. Since by the age of forty the large majority of scientists have been working in their field for at least fifteen years, the studies’ finding strongly suggests that the real reason why scientists over forty rarely produce highly creative work is not that they have simply aged but rather that they generally have spent too long in a given field.

In the argument given, the two portions in boldface play which of the following roles?

A. The first is the position that the argument as a whole opposes; the second is an objection that has been raised against a position defended in the argument.

B. The first is a claim that has been advanced in support of a position that the argument opposes; the second is a finding that has been used in supported of that position.

C. The first is an explanation that the agreement challenges; the second is a finding that has been used in support of that explanation.

D. The first is an explanation that the argument challenges; the second is a finding on which that challenge is based.

E. The first is an explanation that the argument defends; the second is a finding that has been used to challenge that explanation.

24-41 In California, a lack of genetic variation in the Argentine ant has allowed the species to spread widely; due to their being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits the spread of this species in its native Argentina.

A. Due to their being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits

B. Due to its being so genetically similar the ant considers all its fellows to be a close relative and thus does not engage in the kind of fierce intercolony struggles that limit

C. Because it is so genetically similar, the ant considers all its fellows to be close relatives and thus does not engage in the kind of fierce intercolony struggles that limits

D. Because they are so genetically similar to one another, the ants consider all their fellows to be close relatives and thus do not engage in the kind of fierce intercolony struggles that limit

E. Because of being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits